Orange-tip temperature and direct sunlight related activity

PhilBJohnson · Post by **PhilBJohnson** » Tue Apr 23, 2024 5:46 am

It's April 23rd 2024 and local general air temperatures, forecast for today, near Lincoln, Lincolnshire with winds from the north, will reach a maximum of 10ºC.
General air temperatures with wind from the north east, have been much the same, for the last week.
Locally, some male Orange-tip butterflies already "on the wing" and or roosting.

: Thursday April 18th 2024 09:24am Butterfly had emerged from pupa the previous day in local, general air temperatures, forecast, thought to be 12ºC (butterfly roosting about 10cm above old pupal case)

: April 20th 2024 12:48pm roosting male Orange-tip butterfly. Local general air temperatures, forecast to max. at 10ºC with breeze from north east. The butterfly did not significantly change positions in flight that day, other than to open it's wings on a couple of occasions, in direct sunlight.

: April 21st 2024 8:32am Roosting. Forecast 7ºC by 9.00am and 10ºC by 15:45pm when the butterfly finally moved positions, after direct sunlight (sheltered micro-climate possibly slightly warmer).

It was thought that an Orange-tip butterfly's flight activity was minimal with local general air temperatures at 10ºC, in a sheltered micro-climate with direct sunlight. In temperatures of 10-12ºC, an Orange-tip might have achieved flight activity during the warmest part of the day.
In 12ºC or above, flight activity was significantly further in direct sunlight. A significance of understanding detail here, was also in pupal development, that might not take place in the shade below 10ºC, allowing a butterfly to emerge. Temperatures fluctuating between about 10ºC-12ºC might lead to a more staggered local emergence, with male pupae in more direct sunlight emerging first and possibly being more vulnerable, with less flight activity.

A Speckled wood butterfly was seen on the wing in temperatures of 7ºC.
There might be slight differences in temperatures, a butterfly's open wings can absorb or reflect, in direct sunlight warmth, according to wing colour.